Steroidal 3-hydroxy-3, 5-dien-7-ones



STEROIDAL 3-HYDROXY-3,5-DEN-7-ONES Charles W. Marshall, Skokie, Ill., assignor to G. D. Searle & Co., Chicago, 11]., a corporation of Delaware Application September 18, 1956 Serial No. 610,660

11 Claims. (Cl. 260397.4)

No Drawing.

CH: CH:

wherein Z is either a hydroxymethylene radical.

CHOH a carbonyl radical or the ketonic triad R and R" in the triad being either hydrogen, or a hydroxyl or .alkanoyloxy radical. By alkanoyloxy is meant wherein Alk is an alkyl radical.

When Z in the generic formula above is an oxygenated carbon atom, i.e., the hydroxymethylene or carbonyl radical, the compounds represented are 3,17-dihydroxyandrosta-3,5-dien-7-one and 3-hydroxyandrosta-3,S-diene- 7,17-dione, respectively. Alternatively, when Z comprises the specified ketonic triad, the compounds represented are 3-hydroxy-3,5-diene-7,20-diones of the pregnane series, the individual nature of which depends upon the meanings assigned to R and R". Where R' and R" are each hydrogen, the designated compound is an enolic form of 7-oxoprogesterone, namely, S-hydroxypregna- 3,5-diene-7,20-dione. Where R is hydrogen, and R" is hydroxyl or alkanoyloxy, the compounds referred to are 3,17-dihydroxypregna 3,5 diene-7,20-dione and 17-alkanoates thereof, respectively. Where, conversely, R is' hydroxyl or alkanoyloxy, and R" is hydrogen, the compounds represented are enolic 7-oxodesoxycorticosterone and 2l-alkanoates thereof, respectively. Finally, where both R and R" comprise oxygen functions (of the type specified above), the compounds shown are enolized 7-oxo-1l-desoxocortisone and its 17- and/or 21-alkanoic acid esters. In every case, the esters contemplatedboth here in the specification and below in the claims--are characterized by acid residues each containing fewer than States Patent 2,934,545 Patented Apr. 26, 1960 9 carbon atoms, and the term lower, as hereinafter applied to the claimed alkanoates, so delimits.

This application is a continuation-in-part of applicants prior copending application Serial No. 479,661, filed January 3, 1955, now abandoned.

It will be appreciated that the foregoing (and subse-' known in chemistry that compounds distinguished by thepresence of a hydroxyl radical attached to an ethylenic carbon atom as at C in the structure depicted above are constitutionally disposed to participation in equilibrium; mixtures with corresponding saturated keto isomers, ac-,

cording to the relationship In the light of this prior art knowledge, it becomes evident that the enolic interpretation of compounds of the present discovery hereinbefore elaborated actually comprehends not merely the hydroxylated structure shown,

but additionally, the dioxo configuration CH3 CH:

wherein Z has the meaning hereinbefore assigned. Pertinent, also, to the question of scope in the instant disclosure is the prior art teaching that keto groups generally, regardless of position in a given molecule, tend to undergo at least transient enolization (that is to say, addition of a hydrogen ion and, in effect, shifting of the ketonic double bond). It follows that enolization of the subject steroids is presumably not reserved exclusively to the 3-position illustrated, but also involves, at least in some degree, the carbonyl at C with concomitant shifting of the C double bond, and evolution of the structure CH; 0H,

Z being defined as above. Such 7-e nols, of course, will share the disposition characteristic of and described for their 3-isomers to participate in equilibria of the type Z again being defined as before. These latter tautomeric forms-the 7-hydroxy-4,6-diene-3-ones and 4-ene3,7-di-' ones-are thus seen to be, like the 5-ene-3,7-diones discussed above, inherently contemplated in the 3-enolic representation of the compounds of this invention herein elsewhere set forth; and in this respect, the assignment of particular structures and singular names to the substances of the present discovery is to be looked to, not for what is excluded, but rather for that Which is implied thereby. Ultraviolet, infrared, and rotational data clearly demonstrate that the 3-enolic form of the subject compounds is the predominating structure; but any and all of the possible tautomeric modifications thereof must, in the nature of such modifications, be considered equivalent for purposes of the present invention.

The hereinafter claimed compounds comprise a relatively isolated development in the field of steroid chemistry. Only one example of a cyclopentanopolyhydrophenanthrene bearing the distinctive 3-hydroxy-3,5-dien- 7-one configuration is known in the literature; and this material, reported by Barnett et al., J. Chem, Soc., 1946, 526, is a cholesterol derivative remote from the androstadiene and pregnadienes of my discovery. The prior art compound, cholesta-5-ene-3,7-dione, was synthesized to complete a series of dioxocholestanes required as intermediates for preparation of corresponding diamino compounds being investigated as anti-bacterials. No therapeutic utility per se was observed. Barnetts compound, like those of the present disclosure, was found to occur predominantly in enolic form.

Failure in the past to investigate the A/B ring conjugated enolenones could very well be explained on the basis of their extreme reactivity and instability. Thus, for example, solutions of such steroids in any one of several commonly used organic solvents show marked deterioration within a very short time. The mechanism of this deterioration is not-always clear but in some cases the evidence points to a slow condensation of the steroid solute with--particularlysolvents of the ketonic or ester type. Moreover, these steroidal enolenones are extremely sensitive to oxidation, being readily attacked particularly at the hyperactive C (or C position? under even the mildest of experimental conditions. In this. respect they are reminiscent of dihydroresorcinol, a notoriously unstable enolic dione. Notwithstanding the evanescent nature of these compounds in some circumstances, however, I have found them to be quite stable in the pure crystalline state.

The compounds of this invention possess valuable pharmacological properties. Especially the subject com.- pounds are useful because of their selective anti-cortisone activity. Administered conjointly with cortisone, they block the atrophying influence thereof on lymph nodes and thymus, and inhibit, in particular species, cortisoneinduced susceptibility to disease, without in any way impairing the curative eifects of this widely used medicament. Like cortisone, the subject compounds protect against the hyperemia associated with specific types of iritis and inhibit the formation of petechiae and granuloma tissue in selected circumstances. Moreover, certain of these versatile materials exhibit gonadotrophic and anti-atherogenic activities.

The compounds to which this invention relates are relatively insoluble in water, but may be dissolved in dilute alkali and in most of the common organic solvents. The subject compounds may be administered in solid form as tablets or capsules; dissolved or suspended in aqueous media, they may be given parenterally.

Two unique preparative methods have been devised for synthesizing the compounds of this invention. One of these methods uses the same type of starting material a 3-alkanoyloxy-5-eneemployed by Barnett in arriving at the 3-hydroxy-3,5-dien-7-one of the prior art. However, Barnett, after converting his alkanoate to the corresponding 7-oxo compound and then hydrolyzing the 3-ester linkage, proceeds from there to the desired prodnot by means of a laborious multi-step operation which involves 1) 5,6-halogenation with bromine in carbon disulfide, (2) oxidation with chromic acid in a poly-phase solvent system to the 3,7-dioxo-5,6-dibromo derivative, and finally (3) dehalogenation with zinc and acetic acid. As opposed to this, I have found that the 3-hydroxy-5- en-7-one obtained from an appropriate 3-alkanoyloxy-5- enic starting steroid can, surprisingly, be converted to the corresponding dienone in a single step-with resultant economy of time and materials-by subjecting this intermediate to short-term Oppenauer oxidation, taking particular care that the product produced is rapidly removed from the presence of other carbonyl compounds and substances-for example, aluminum salts-capable of promoting interaction therewith. In a preferred embodiment of this latter process, the oxidation is carried out using an aluminum alkoxide in toluene and cyclohexanone at temperatures of the order of 140 to 160 centigrade for periods of time ranging from 15 minutes to not longer than 1 /2 hours. The reaction product is straightway extracted into a water-immiscible solventfor example, dichloromethaneand the resultant solution, in turn, is rapidly freed of aluminum salts by washing with, for example, dilute aqueous muriatic acid. The purified solution is then immediately extracted with dilute aqueous alkali, in which the desired enolenone is preferentially soluble. From this aqueous solution, the enolenone is precipitated upon acidification.

The foregoing short-term Oppenauer procedure has been used for the preparation of 3-hydrxyandrosta-3,5- diene-7,17-dione and 3-hydroxypregna-3,5-diene-7,20-dione as detailed in Examples 1 and 3 hereinafter, respectively. Essentially the same methodmodified only to provide, preferably, protection, as. by esterification or the equivalent, for any 17- or 2l-hydroxyls presentmay likewise be employed for preparing such of the compounds of the present invention as l7-acetoxy-3-hydroxyandrosta 3,5 dien 7 one, 17 acetoxy 3 hydroxypregna 3,5 diene 7,20 dione, 21 acetoxy 3 hydroxypregna 3,5 diene 7,20 dione, l7a,2 1 diacetoxy 3 hydroxypregna 3,5 diene 7,20 dione, and the alcohols corresponding to these compounds, namely, 3,17 dihydroxyandrosta- 3,5 dien 7 one, 3,17 dihydroxypregna 3,5 dien 7,20 dione, 3,21 dihydroxypregna 3,5 diene 7,20 dione, 21 acetoxy 3,1711- dihydroxypregna 3,5 diene 7,20 dione, and 3,17a,21- trihydroxypregna 3,5 diene 7,20 dione. However, the appropriate 3-alkanoyloxy-5-ene starting materials are not as readily available for these latter products as for those preceding, wherefore a different method of deriving the compounds of this invention starting with corresponding 3-oxo-4-enes has been developed. This secondand generally preferableprocedure takes advantage of the fact that ketal formation with ethylene glycol at the 3- position of a 4,5-unsaturated steroid molecule causes shifting of the double bond to A5, thereby efiecting necessary allylic' activation of the C methylene. By the second procedure, an appropriate 3-oxo-4-enic steroid is converted to the corresponding 3-ethylene ketal (where a 17-keto1 side chain is present, the C carbonyl is preliminarily rendered unreactive by esterification of the 21- hydroxyl; and if there be a hydroxyl at C protection thereof-by esterification or the equivalentis advisable prior to ensuing oxidation), which, in turn, is selectively oxidized with a tertiary lower alcohol ester of chromic acidfor example, tertiary butyl chromate, tertiary amyl chromate, or the equivalent-in an inert, relatively nonpolar solvent such as carbon tetrachloride, benzene, or petroleum ether, there being present, preferably, l0-20% of a lower alkanoic acid (for example, acetic acid) and 25% of a compatible dehydrating agent (for example, acetic anhydride), and the reaction being run at temperatures ranging from 35 to centigrade for periods of time generally not longer than 24 hours. The 5-ene-3, 7-dione 3-ethylene ketal thus produced, upon hydrolysis with, for example, aqueous acetic acid at -100 centigrade for 10 minutes to half an hour, yields the cone-- sponding enolenone. 1

Perhaps the most interesting aspect of the second process of mydiscovery, apart from the unusual and valuable products which it provides, is the fact that its successful application depends upon a contradiction in chemical behavior of the key intermediate therein. Although prior art confirms that steroidal 5-en-3-one 3-ethylene ketals may be amenable to allylic modification (specifically, bromination), such modification has been carried out under strictly neutral conditions. On the other hand, it is well-known in the art that ketals of the class here disclosed are highly vulnerable to acid-catalized exchange reactions with organic acids, reverting in such circumstances to the 3-oxo-4-enic compounds whence derived. This being true, survival of the subject ketals in contact at elevated temperatures with the small amounts of chromic acid probably present in the reaction mixture during the oxidation step in the instant procedure is not only extremely useful, but contrary to expectation.

With respect to the hydrolytic treatment of the instant ketals outlined above, it should be remarked that the technique there disclosed has no eifect on ester linkages in the 17 06- or 21-position. The 170: and 21 esters, which are equivalent to corresponding alcohols for the purposes of this invention, may be cleaved, either before or after ketal hydrolysis, by-standing in dilute alkali for a few minutes at room temperature.

The following examples describe in detail certain of i the 3-hydroxy-3,5-dien-7-onesillustrative of the present invention and methods which have been devised for their prepartion. However, the invention is not to be construed as limited thereby, either in spirit or in scope, since it will be apparent to those skilled in the art of organic synthesis that many modifications, both of materials and of methods, may be practiced without departing from the purpose and intent of this disclosure. In the examples hereinafter detailed temperatures are given in degrees centigrade C.), pressures in millimeters (mm.) of mercury, and relative amounts of materials in parts by weight, except as otherwise noted. 7 The symbol N as used herein stands for normal, a term designating concentration in equivalent Weights of solute per unit volume of solution.

Example 1 (A) .iB-acetoxyandrost-S-ene-ZI7-a'i0ne.To a solution of 160 parts of dehydroepiandrosterone acetate in 1785 parts of glacial acetic acid at 5055 C. is added portion-wise with agitation over a 2-hour period 114 parts of chromium trioxide. The reaction mixture is then maintained with agitation for an additional 2 hours at 50-55 C., following which it is cooled to room temperature; and 40 parts of methyl alcohol is then added to destroy excess hexavalent chromium. The mixture is concentrated to one-fourth its original volume by vacuum distillation at 40-45 C., whereupon the concentrate is combined with 3500 parts of ice cold water. The resultant mixture is twice extracted with 675-part quantities of ethyl acetate; and these extracts are then combined and washed successively with three SOD-part quantities of water, three SOO-part quantities of 2% aqueous caustic, two 500-part quantities of 2% aqueous muriatic acid, three 500-part quantities of saturated aqueous sodium bicarbonate, two SOS-part quantities of water, and, finally, one 300part quantity of saturated brine. The Washed extract is next dried over anhydrous sodium sulfate, filtered, and stripped of solvent by vacuum distillation. The solid crystalline residue is recrystallized from methyl alcohol to give, in good yield, SB-acetoxyandrost-S-ene- 7,17-dione, Ml. 182-183 C.

(B) 3,8-hya'r0xyandr0st-5-ene-7J7-dione.+The acetate of the foregoing part A is hydrolyzed by dissolving 42 parts thereof in 1700 parts of methyl alcohol, adding 200 parts of dioxane and 231 parts of 2 N aqueous caustic soda, and letting stand under an atmosphere of nitrogen with agitationat room temperature for 4 hours. The reaction mixture is then poured into 10,500 parts of cold water containing parts of 5 N aqueous muriatic, acid. The precipitated product is collected on a funnel, washed thereon with water, suspended in water. to further purify, again recovered on a funnel, and finally once more washed on the funnel with water. The 3fi-hydroxy-' androst-5-ene-7,17-dione thus obtained, after drying in air, shows M.P. 235-238 C. (corr.).

(C) 3-hydroxyandr0sta-3,5-diene-7,17-dione.-A solution of 20 parts of3B-hydroxyandrost-S-ene-7,l7-dione in 955 parts of toluene is dried by azeotropic distillation under an atmosphere of nitrogen. To such solution, at 160, is added 190 parts of cyclohexanone, followed over a 10-minute period by 30 parts of aluminum isopropoxide dissolved in parts of toluene, the system being maintained in an anhydrous condition by continuous slow distillation of toluene throughout. Heating at C. is continued for an additional 25 minutes, whereupon the reagents are cooled to 5 C., then mixed well with 6700 parts of cold dichloromethane and 5000 parts of cold 2% aqueous sulfuric acid containing 250 parts of sodium chloride. The aqueous phase is drawn off and mixed well with 3300 parts of fresh cold dichloromethane, then again separated, and finally discarded. The organic solvent solutions are combined and washed with 2500 parts of cold 2% aqueous sulfuric acid containing 125 parts of sodium chloride, then thrice rapidly extracted with 2500-part portions of cold 2% aqueous caustic soda, each extract as obtained being immediately poured into an excess of cold 5% aqueous muriatic acid. The product thus precipitated is collected on a filter, washed thereon with water, and dried in air to a yellow powder. Crystallization from methyl alcohol and from acetone yields dimorphous 3-hydroxyandrosta- 3,5-diene-7,l7-dione, one form showing MP. 215- 216 C., the other MP. 227-228" C. From acetone, the high-melting form is invariably obtained. Ultraviolet spectra (.002% in methyl alcohol) show two peaks typical of fi-hydroxy-w'y-dienones, the larger with a maximum at 320 millimicrons and a molecular extinction of 24,700, and the other with a maximum at 389 millimicrons and a molecular extinction of 8200. Specific rotation in dioxane solution is -25 6, in chloroform solution, 0. infrared spectra manifest principal absorption bands at 3.02, 5.74, 6.06, 6.28, 6.40, 7.65, 8.25, 8.55, and 9.45 i. The product thus obtained may be represented by the enolic formula Example 2 (A) acet0xyandr0sI-5-ene-3,7-dione 3 ethylene ketaL-To a solution of 20 parts of testosterone acetate 3-ethylene ketal-preparable by the method of Antonucci et al., J. Org. Chem, 17, 1341 (l952)in 320 parts of chloride solution of tertiary butyl chromate-anhydrousand free of tertiary butyl alcohol-assaying 29 parts of chromium trioxide. Heating at 50 55 C. with agitation is continued for 18 hours longer, after which the reactants: are chilled to 16 C. and combined during 30 minutes 7 i with 860 parts of a 10% aqueous solution of oxalic acid dihydrate. The mixture, no longer cooled, is maintained with agitation for an additional hour, whereupon 1000 parts of water is introduced and the mixture subsequently extracted with 1500 parts of chloroform, and then reextracted with 375 parts of chloroform. The two chloroform extracts are combined and washed, successively,

once with water, 4 times with aqueous sodium carbonate, twice with water, and finally once with saturated brine. The washed extracts are dried over anhydrous sodium sulfate and stripped of solvent by "vacuum distillation under a nitrogen atmosphere. The residual 176- acetoxyandrost-S-ene-3,7-dione 3-ethylene ketal light buff in coloris taken to hydrolysis as detailed in the following part B of this example without further work-up. (B) 17l3-acet0xy 3-hydr0xyandrosta-3,5-ciien-7-0ne.- In an atmosphere of nitrogen, 16 parts of the 3-ethylene ketal of the preceding part A is mixed with 400 parts of glacial acetic acid and heated with agitation at 100 C. for 5 minutes. With continued agitation at 100 C., 100 parts of hot distilled water is introduced over a 5-minute period. Heating with agitation is continued for 25 minutes more, whereupon the mixture is quickly chilled to 5C. and dumped into 3500 parts of cold water. The solids thus precipitated are collected on a filter, washed thereon with cold water, then resuspended in 1500 parts of cold water, again recovered on a filter, and once more washed thereon with cold water. After drying in air, the resultant near-White powder is alternately crystallized from methyl alcohol and ethyl acetate to yield slender blades, M.P. 245246 C. (corn). The 17fi-acetoxy-3- hydroxyandrosta-3,5-dien-7-one thus obtained is characterized by a maximum in the ultraviolet spectrum at 320 mg, log E being 4.37 (for a methyl alcohol solution). The specific rotation in 0.89% dioxane solution is 2 69. The infrared spectrum shows absorption bands at 3.19, 5.78, 6.18 (shoulder), 6.28 and 6.50 The product may be represented by the formula I CHa 246 C. (corn).

Example 3 (A) 3B-acetoxypregn-5-ene-7,20-dione.+To a solution of 15 parts of pregnenolone acetate in approximately 100 parts of purified carbon tetrachloride is added with agitation at 50-55 C. over a 90-minute period a mixture consisting of 63 parts of glacial acetic acid, 16 parts of acetic anhydride, and 400 parts of purified carbon tetrachloride containing tertiary butyl chromate assaying 22 parts of chromium trioxide. The reactants are maintained with agitation at 5055 C. for an additional 12 hours, then cooled to room temperature and thereupon thoroughly mixed during 1 hour with 600 parts of a aqueous solution of oxalic acid dihydrate. The carbon tetrachloride layer is separated and washed, successively, 4 times with 5% aqueous sodium carbonate, 3 times with water, and once with saturated brine. The solution is then dried over anhydrous sodium sulfate and stripped of solvent by vacuum distillation. The residue, crystallized alternately from 1:1 (by volume) benzene-petroleum 8 ether and methyl alcohol, affords heavy white needles of pure 3fi acetoxypregn 5 ene7,20-dione, MP. 153-1551 C. (corn), [u] S, y max. 236mm, and log E 4.10, specific rotation and ultraviolet absorption being'observed in methyl alcohol solution. Workup of thte mother liquors yields an additional amount of product equimolecularly mixed with unreacted starting material. Such mixture is separable by chromatography or may be reoxidized with tertiary butyl chromate to increase the overall yield of the instant process.

(:3) 3pJryrircxypregn-S-ene-7,20-di0ne.A mixture of 10 parts of 3,B-acetoxypregn-S-en-7,20-dione, 400 parts of methyl alcohol, 50 parts of dioxane, and 50 parts of 2.2 N aqueous caustic soda is allowed to stand with agitation at 25 C. for 3 hours. The mixture is then diluted with 2500 parts of cold water containing 50 parts of 2.4 N aqueous muriatic acid, and the precipitate which results is collected by filtration.- Washed first on the filter with'water, the precipitate is next resuspended in 2000 parts of water for additional purification, following which it is again recovered on a filter, Washed additionally thereon with still more water, and finally dried in air. The 3,B-hydroxypregn-5-ene-7,20-dione thus obtained is a white powder which, crystallized from methyl alcohol, shows MP. 209 -210 C. (corn). Workup of the mother liquor'aflords additional product in the form of a 1:1 molecular complex with a dienone (as shown by ultraviolet analysis) not presently identified. Crystallization of the complex from ethyl acetate permits recovery of additional 3fi-hydroxypregn-5-ene-7,20-dione therefrom. The subject product crystallizes from methyl alcohol in the form of long, rectangular fiat blades, and is characterized as follows: [a] -72, 7 max. 238 mg, and log E 4.12, all values being determined in methyl alcohol solution. Absorption bands in the infrared spectrum occur at 2.91, 5.94, 6.03, and 6.15

(C) 3-11 droxypregna-3,5-diene-7,20 -a'i0ne.A solution of 2 parts of 3B-hydroxypregn-5-en-7,20-dione in 195 parts of dry toluene is heated to. C. under an atmosphere of nitrogen and sufficient solvent distilled therefrom (approximately one-third volume) to dry out the system azeotropically. Distillation is then stopped and to the' vigorously refluxing material (still at 160 C. under nitrogen) is added 19 parts of redistilled cyclohexanone, followed dropwise by a solution of 3 parts of aluminum isopropoxide in 15 parts of dry toluene. A yellow color develops immediately. Heating at 160 C. under nitrogen is continued for an additional 45 minutesbeyond which time there is danger of diminishing yields resulting from the highly reactive nature of the desired product whereupon the mixture is cooled to 5 C., diluted with 670 parts of cold dichloromethane, and extracted with 500 parts of cold 2% aqueous sulfuric acid containing 25 parts of sodium chloride. The organic layer is separated and combined with that derived by extraction of the aqueous layer with an additional 330 parts of cold dichloromethane. The combined toluene-dichloromethane extracts are again washed with cold 2% aqueous sulfuric acid (250 parts containing 12 parts of sodium chloride) at which point the desired enolenone may be effectively separated in one step from deleterious impurities by dissolution in alkali and rapid precipitation with acid. Accordingly, the acid washed toluene-dichloromethane solution is quickly extracted three times with 250-part portions of cold 2% aqueous caustic soda, each alkaline extract as it is obtained being immediately removed into an excess of 5% aqueous muriatic acid. The precipitated material which results is collected on a filter, washed thereon with water, and dried in air to a light yellow powder. Crystallization from methyl alcohol gives fine cottony needles of 3-hydroxypregna-3,S-diene- 7,20-dione, MP. 255-259 C. The product shows ultraviolet absorption peaks in methyl alcohol at 321 and 389 m with molecular extinction coeflicients of 21,200 and 3000, respectively. The infrared spectrum as determined in a potassium bromide disc is characterized by absorption bands at 3.20, 5.88, 6.18, 6.27, and 6.5,. The product is represented by the enolic formula C=O CH3 Example4 (A) 21-acetoxypregn-S-ene-3,7,20-trione 3-ethylene ketals.-To a solution of 12 parts of desoxycorticosterone acetate S-ethylene ketal-preparable by the method of Antonucci et al., J. Org. Chem., 17, 1369 (1952)-in 960 parts of carbon tetrachloride at 50-55" C. is added 158 parts of glacial acetic acid and 43 parts of acetic anhydride, following whichat the same temperature, over a one-hour period, and with agitation-is introduced 250 parts of a carbon tetrachloride solution of tertiary butyl chromateanhydrous and free of tertiary butyl alcoholassaying 16. parts of chromium trioxide. Heating at 5055 C. with agitation is continued for 17 hours longer, after which the reactants are cooled to 18 C. and combined during 15 minutes with 500 parts of a 10% aqueous solution of oxalic acid dihydrate. The mixture is maintained with agitation for an additional hour, whereupon 1000 parts of water is introduced and the mixture is then extracted with 1100 parts of chloroform. The chloroform layer is temporarily set aside and the aqueous phase, diluted with an additional 1000 parts of water, is twice reextracted with 375-part portions of fresh chloroform. All three chloroform extracts are then combined and washed, successively, once with water, 4 times with 5% aqueous sodium carbonate, 3 times'with water, and finally once with saturated brine. Thus purified, the extracts are dried over anhydrous sodium sulfate and stripped of solvent by vacuum distillation under a nitrogen atmosphere. The residual 21-acetoxy-pregn- 5-ene-3,7,20-trione 3-ethylene ketalnear white in color I is taken to hydrolysis as detailed in the ensuing part B" of this example without further work-up. The pure ketal, which may be recrystallized from acetone, melts at 251.5-254 C. (uncorr.), and in methyl alcohol solution exhibits a maximum in the ultraviolet spectrum at 240 mu, log E being 4.10. Y

(B) 21 acetoxy 3 hydroxypregna 3,5 diene 7,20- dione.ln an atmosphere of nitrogen, 11 parts of the 3- ethylene ketal of the preceding part A is mixed with 380 parts of glacial acetic acid and heated with agitation at 100 C. until solution is completed, approximately 5 minutes being required. With continued agitation at 100 C., 90 parts of hot distilled water is introduced over a 5 minute period. Heating with agitation is continued for 25 minutes more, whereupon the mixture is quickly cooled to 5 C. and then intimately combined with 4000 parts of cold 5% aqueous sodium chloride. -Material thus precipitated is collected on a filter and washed thereon with cold 5% aqueous sodium chloride. Additional purification is achieved by resuspending the filter cake. in cold 5% aqueous sodium chloride, again recoveringthe pre-' cipitate on a filter, and once more washing thereon, this time with cold water. After drying in air, the product, a tan powder at this point, is alternately crystallized from methyl alcohol and acetone to give fine needles, nearly white in color, M.P. 229-230 C. (corn). The 21-acetoxy-3-hydroxypregna-3,5-diene-7,20-dione thus obtained is characterized by maxima in the ultraviolet spectrum at 320 and 390 m log 'E b being 4.37 and 2.98, respectively (for a'methyl alcohol solution); The specific rotation in asses I 1d 0.5% dioxane solution is 182, in 0.5% chloroform solution, +29. The infrared spectrum shows absorption bands at 3.17, 5.72, 5.81, 6.19, 6.25, and 6.48,u. The product may be represented by the formula CH=O-CCH;

Example 5 3,2I-dihydroxypregna-3,5-diene-7,20-di0ne. Under a nitrogen atmosphere, 7 parts of 21-acetoxy-3-hydroxypregna-3,5-diene-7,20-dione, preparable by the method of the preceding Example 4, is suspended in 50 parts of methyl alcohol and rendered soluble by the rapid (less than 2 minutes) addition, with agitation, of a mixture consisting of 200 parts of 1% aqueous potassium hydroxide and parts of water. After 9 minutes, parts of 2% aqueous acetic acid is introduced over a 3- minute period, agitation being continued throughout and for 1 minute longer. The reactants are then quickly cooled to 0 C. and diluted with 540 parts of cold 10% aqueous sodium chloride. The precipitate which results is collected on a filter, washed thereon with cold 5% brine, additionally washed by slurrying with 900 parts of cold 5% brine, refiltered, and finally washed on the filter with parts of cold water, in that order. Further purification is achieved by crystallizations from methyl alcohol, isopropyl alcohol, and acetone. The product thus obtained 3,21-dihydroxypregna-3,5-diene-7,20-dione-shows a characteristic peak in the ultraviolet spectrum at 321 m in methyl alcohol, log E being 4.35. The infrared spectrum is distinguished by principal bands at 2.81, 3.19, 5.85, 6.15, 6.22, and 6.45,u. The product may be represented by the formula onion C=O CE: I

Example 6 (A.) 2l-hydroxypregn-5-ene-3,7,20 trione 3-ethylene ketal.-To a solution of 11 parts of 21-acetoxypregn-5- one-3,7,20-trione 3-ethylene ketalExample 4A above in 320 parts of methyl alcohol is added, with agitation at 25 C. under an atmosphere of nitrogen, 115 parts of a 1% '(w./v.) solution of potassium hydroxide in methyl alcohol. With continued agitation, the reagents are let stand 5 minutes, following which 16 parts of methyl alcohol containing one equivalent (0.5 part) of water is introduced. Agitation is continued 4 minutes longer, at which point the solution is chilled and 240 parts of 1% aqueous acetic acid is added over a 5-minute period. The reagents are then mixed with 4000 parts of cold 5% aqueous sodium chloride, causing precipitation of the desired 21hydroxypregn-S-ene-3,7,20-trione 3-ethylene ketal. The product is collected on a filter, washed thereon with cold dilute brine, additionally washed by suspension in cold dilute brine, refiltered, and washed on the filter with 400 parts of cold water, in that order. Dried 11 in air, the material is taken directly to hydrolysis as detailed'below, withoutrecrystallization. i

12.) 3,21-dihydroxypregna'-3,5-diene-7,20-dione.-- l-Iydrolysis of the S-ethylene ketal of the foregoing part A of this example is achieved by heating 5 parts thereof in 245 parts of 80% aqueous acetic acid at 100 C. under a nitrogen atmosphere according to the technique detailed in Example 4B above. The brine-and-water washed solids obtained are dried in air to a yellow powder which, upon crystallization from methyl alcohol, isoproply alcohol, and acetone, respectively, affords pure 3,21-dihydroxypregna,3,S-diene-7,20}dione, identical in all respects with that produced in the preceding Example 5.

Example 7 (A) 17oz acetoxypregn 5 ene-3,20-dine 3-ethylene ketaL-To a solution of 24 parts of 17a-acetoxyprogesterone in 765 parts of dry benzene is added 210 parts of ethylene glycol and 1 part of p-toluenesulfonic acid monohydrate. The mixture is agitated vigorously and treated at reflux for 2% hours, during which time azeotropically distilled water is collected and separated. Then for 4 /2 hours the agitated mixture is slowly distilled, removing additional water and part of the benzene. In the course of the latter heating period, the volume of the reaction mixture is kept constant by gradual addition of dry benzene. The mixture is next cooled to room temperature and, after diluting with 1250 parts of .vater,

extracted with 675 parts of ethyl acetate. The aqueous residue is re-extracted with 225 parts of ethyl acetate, following which the two ethyl acetate extracts are combinedand washed successively with 5% aqueous sodium bicarbonate, Water, and saturated brine. The washed extracts are then driedover anhydrous sodium sulfate and stripped of solvent by vacuum distillation. Two recrystallizations of the solid residue from methyl alcohol provide fine, hairy needles of the methyl alcohol solvated product, M.P. 239241 C. (uncorr.). The 17a-acetoxypregn-5-ene-3,20-dione 3-ethylene ketal thus obtained, after desolvation for 3 hours in vacuo at 140 C., is transparent over the range 230-360'mn when dissolved 0.011% in methyl alcohol. Incorporated in a potassium bromide disc, the product shows absorption bands'in the infrared spectrum at 5.78, 5.83, 8.00, 9.02, and 9.28

(B) 17a-acet0xypregn 5 ene-3,7,20-tri0ne 3-ethylene ketal.A solution of parts of the crystalline methyl alcohol solvate of 17ot-acetoxypregn-5-eue-3,20-dione 3- ethylene ketal-preparable by the method of Example 7A above-in approximately 1100 parts of carbon tetrachloride is subjected to distillation until approximately 500 'parts of distillate containing the azeotropically removed methyl alcohol is collected and discarded. To the residual carbon tetrachloride solution at 5055 C. is added 50 parts of glacial acetic acid and 13 parts of acetic anhydride, following which-at the same temperature, over a twenty minute period, and with agitationis introduced a mixture consisting of 50 parts of glacial acetic acid, 12 parts of acetic anhydride, and 200 parts of a carbon tetrachloride solution of tertiary butyl chromate-- anhydrous and free of tertiarybutyl alcoholassaying 13 parts of chromium tn'oxide. Heating at 50-55 C. with agitation is continued for 18 hours, after which the reactants are chilled to 15 C. and combined during minutes with 500 parts of a 10% aqueous solution of oxalic acid dihydrate. The mixture, no longer cooled, is maintained with agitation for an additional hour, whereupon the layers are separated and the aqueous residue reextracted with 320 parts of carbon tetrachloride. The two carbon tetrachloride extracts are combined and washed, successively, twice with 5% aqueous sodium carbonate, 3 times with water, and finally with saturated brine. Thus purified, the extracts are dried over anhydrous sodium sulfate and stripped of solvent by vacuum distillationunder a nitrogen atmosphere. The

orous reflux for 5 /2 hours, during which azeotropically white solid residue is recrystallized twice from ethyl acetate to afford pure 17a-acetoxypregn-5-ene-3,7,20-trione 3 -ethylene ketal, M.P. 242243 C. (uncorr.). The product is characterized in methyl alcohol solution by a maximum at 240 m log E being 4.11.

(C) 17oz acetoxy 3 hydroxypregna 3,5 diene- 7,20-dione.In an atmosphere of nitrogen, 14 parts of the l7a-acetoxypregn 5-ene-3,7,20-trione 3-ethylene ketal of the preceding part B is mixed with 500 parts of glacial acetic acid and heated with agitation at C. until solution is compiete, less than 5 minutes being required. With continued agitation at 100 C., parts of hot distilled water is rapidly introduced. Heating with agitation is continued for 25 minutes more, whereupon the mixture is quickly cooled to 5 C. and then intimately combined with 1200 parts of cold 5% aqueous sodium chloride. The precipitated solid is extracted from the mixture with two 500-part portions of dichloromethanc, following which the combined extracts are washed with 5% aqueous sodium chloride, dried over anhydrous sodium sulfate, and finally stripped of solvent by vacuum distillation under a nitrogen atmosphere. The light yellow residual solid, upon recrystallizing twice from methyl alcohol, yields the nearly white crystalline product, M.P. 225-227.5 C (uncorr.). The l7a-acetoxy-3-hydroxypregna-3,5-diene-7,20-dione thus obtained is characterized by a maximum in the ultraviolet spectrum at 3l7318 m log Em being 4.36 for a methyl alcohol solution. In a potassium bromide disc, the product reveals principal absorption bands in the infrared spectrum at 2.93, 5.77, 5.89, 6.07, 6.20, and 6.30 The product may be represented by the formula Example 8 (A) 17oc,21 diacetoxypregn 5 ene 3,20 dione 3-ethylene ketal.To a solution of 38 parts of Reichsteins substance S diacetate (17u,21-diacetoxypregn-4- one-3,20-dione) in 1760 parts of dry benzene is added 295 parts of ethylene glycol and 1 part of p-toluenesulfonic acid monohydrate. The mixture is heated at vigdistilled Water is collected and separated. The mixture is then cooled to room temperature and, after diluting with 1600 parts of water, extracted with 900 parts of ethyl acetate. The extract is washed several times with water,

'twice with 5% aqueous sodium carbonate, twice more with water, and finally with saturated brine. It is then dried over anhydrous sodium sulfate and stripped of solvent by vacuum distillation. Crystallization of the oily residue from a 1:10 mixture of acetone and methyl alcohol, and again from either this mixture or pure alcohol, gives dimorphoric 170;,21-diacetoxypregn-5-ene-3,20-dione 3-ethylene ketal, M.P. 115-l28 C. and 164- 166 C., respectively. Both forms, as thus obtained, are monosolvated with methyl alcohol. The lower melting form resolidifies above C. and melts again at 162-165 C Dried 2 hours in vacuo at 100 C., it loses its alcohol of crystallization, shows a] D32 in chloroform, and is transparent over the range 230-260 me when dis: solved in .002% methyl alcohol. The higher melting form, desolvated at 100 C. in vacuo, shows in chloroform, is transparent in .002% methyl alcohol I by absorption bands in the infrared spectrum at 5.71, 5.78,

8.07, and 9.25;. Desolvation does not alter the melting point of either form. Workup of the mother liquors yields unreacted starting material.

(B) 17u,21-diacetoxyprgn-S-ene-3,7,20-trione 3-ethyl ene ketaL-To a solution of 20 parts of the ethylene ketal of the foregoing part A of this example in 665 parts of purified carbon tetrachloride is added 66 parts of glacial acetic acid and 22 parts of acetic anhydride, following which a mixture consisting of 66 parts of glacial acetic acid, 22 parts of acetic anhydride, and 335 parts of a purified carbon tetrachloride solution of tertiary butyl chromate assaying 25 parts of chromium trioxide is introduced with agitation at 50-55 C. over a 1-hour period. Heating and agitation is continued for an additional 16 hours, at which point the reactants are, successively, cooled to 18 C., maintained in intimate contact with 770 parts of a 10% aqueous solution of oxalic acid dihydrate for 1 hour, diluted with 1350 parts of water, and finally extracted with 835 parts and 560 parts, respectively, of dichloromethane. The extracts are combined, and washed once with water, 4 times with 5% aqueous sodium carbonate, 3 times with water, and lastly with saturated brine, in that order. After drying over anhydrous sodium sulfate, the washed extracts are stripped of solvent by distillation in vacuo. The near-white crystalline residue is 17ot,21-diacetoxypregn-5-ene-3,7,20-trione 3-ethylene ketal, which may be taken directly to hydrolysis as in the following part C of the this example. Recrystallization from mixtures of acetone and methyl alcohol yields dimorphic forms of the ketal, M.P. 142-144 C. and 157-159 C. (uncorr.), respectively, the lower melting form being converted to the higher melting form upon gradual heating above its melting point. In methyl alcohol solution, the product shows an ultraviolet peak at 240 m with the log E being 4.08; incorporated in a potassium bromide disc, the product exhibits characteristic bands in the infrared at 5.72, 5.75-5.79, 6.02, 6.15, 8.10, 9.02, and 9.28

(C) 1704,21-diacetoxy-3-hydr0xypregna-3,5 diene 7, 20-dione.-A mixture of 5 parts of 17a,21-diacetoxypregn- 5-ene-3,7,20-trione 3-ethylene ketal and 230 parts of 80% aqueous acetic acid is heated with agitation at 100 C. for 25 minutes. The mixture is then cooled and precipitated with an excess (about 10 volumes) of cold 5% brine. Worked up by the procedure described in Example 4B above, there is obtained a tan powdery product, which crystallized alternately from methyl alcohol and acetone, affords pure 17u,21-diacetoxy-3-hydroxypregna-3,S-diene- 7,20-dione as clusters of faintly yellow, small, fiat blades, M.P. 251252 C. (corn). The product shows M1 -258 in dioxane, and is characterized in methyl alcohol solution by an ultraviolet peak at 320 m with log E being 4.32. The infrared spectrum reveals characteristic bands at 3.03, 5.77, 5.85, 6.05, 6.23 and 6.34 m The following structural formula is characteristic C-O CH Example 9 3,17a,21-trihydroxypregna-j,S-dieneJJO-dione.--To a suspension of parts of 17a,2l-diacetoxy-3-hydroxypregna-3,5-diene-7,20-dione in 35 parts of methyl alcohol under a nitrogen atmosphere is rapidly (within 2 minutes) added at 25 C. during vigorous agitation a mixture consisting of 189 parts of 1% aqueous potassium hydroxide 14. and 150 parts of water. With continued agitation, solution occurs; and after 9 minutes there is introduced over a 3-minute period a mixture of 4 parts of acetic acid and 220 parts of cold water. Agitation is continued 1 minute longer, whereupon the reactants are chilled to 0 C. and diluted with 720 parts of cold 10% brine. The resultant precipitate is collected on a filter, washed thereon with cold 5% brine, additionally washed by suspension in 1125 parts of cold 5% brine, refiltered, and finally washed on the filter with 225 parts of cold water. Dried in air, the amorphous, essentially pure 3,17a,21-trihydroxypregna- 3,5-diene-7,20-dione thus obtained shows, on dissolution in methyl alcohol, a peak in the ultraviolet spectrum at 319 mp, log E being 4.30. The infrared spectrum is characterized by principal absorption bands at 2.84, 2.95, 3.07, 5.90, 6.08, 6.25, and 6.47 2. The product has enolic formula 3112015! C=O CH3 l...o

Example 10 (A) 17a,21-dihydroxypregn-5-ene-3,7,20-trione 3-ethylene ketaL-To a solution of 23 parts of 17u,2l-diacetoxypregn-5-ene-3,7,20-trione 3-ethylene ketal-preparable by the method of Example 8B abovein 790 parts of methyl alcohol under an atmosphere of nitrogen is added, at 25 C. with agitation, 210 parts of a 2% (w./v.) solution of potassium hydroxide in methyl alcohol. After 5 minutes, 40 parts of aqueous methyl alcohol containing .one equivalent of water is introduced, following which the reaction mixture is let stand for 4 minutes, then made just acid over a 5-minute period with 900 parts of ice-cold 1% acetic acid, agitation being continuous throughout these operations. The mixture obtained by this means is intimately combined with 10,000 parts of cold 5% brine, whereupon precipitated material is collected on a filter and, successively, washed thereon with cold dilute brine, additionally washed by suspension in cold dilute brine, again filtered out, and finally washed on the filter with 1000 parts of cold water. 17a,2l-dihydroxypregn-S-ene- 3,7,20-trione 3-ethylene ketal thus prepared is taken directly to hydrolysis as detailed in part B of this example hereinafter.

(B) 3,17a,21-trihydroxypregna-3,5-diene-7,20-dione. A mixture of 9 parts of 17u,2l-dihydroxypregn-S-ene- 3,7,20-trione 3-ethylene ketal, prepared as described in the preceding part A of this example, and 800 parts of aqueous acetic acid is heated at C. for 25 minutes. An excess (approximately 7500 parts) of cold 5% brine is then added, following which the precipitated product is worked up according to the technique detailed for the acetoxy ketal of Example 4B above. The amorphous 3,17oc,2l trihydroxypregna 3,5 diene-7,20-dione thus prepared is identical in all respects with that obtained by the method of the foregoing Example 9.

What is claimed is:

1. A compound of enolic formula 0 CH5 ll HO -O 2. A compound of enolic formula HO O 3. A compound for enolic formula C=O C 3 1 A j up,

Q 4. A compound of enolic formula wherein R is a lower alkanoyloxy radical,

5. A compound of enolic formula C=O a 6. A compound of enolic formula CHzR wherein R and R are lower alkanoyloxy radicals wherein Z is a member of the group consisting of carbonyl, ,B-hydroxymethylene, and s -(lower alkanolyloxy)- methylene radicals and radicals of the formula R and R" being selected from the group consisting of hydrogen, and hydroxy and lower alkanoyloxy radicals.

9. In a process for the manufacture of compounds of enolic formula wherein Z in a member of the group consisting of carbonyl, fi-hydroxymethylene, and ,B-(lower alkanoy1oxy)- methylene radicals and radicals of the formula R and R being selected from the group consisting of hydrogen, and hydroxy and lower alkanoyloxy radicals, the step which comprises contacting, through the agency of an inert non-polar organic solvent medium, at temperatures between 35 and 65 centigrade and for periods of time rangingfrom 2 to 24 hours, a S-ethylene ketal of the formula CHz -O oHro with a tertiary lower alcohol ester of chromic acid, in

the presence of an alkanoic acid and the anhyride of an alkanoic acid, said acid and acid anhydride each con- 17 taining at least 2 and less than carbon atoms, Z in the formula for the ketal being a member of the group consisting of carbonyl and fl-(lower allcanoyloxy)methylene radicals and radicals of the formula CEIzR wherein R' and R" are selected from the group consisting of hydrogen and lower alkanoyloxy radicals.

10. In a process for the manufacture of compounds of enolic formula wherein Z is a member of the group consisting of carbonyl, fl-hydroxymethylene and ,B-(lower a1kanoyloxy)- methylene radicals and radicals of the formula R' and R being selected from the group consisting of hydrogen, and hydroxy and lower alkanolyoxy radicals, the step which comprises contacting, through the agency of an inert non-polar organic solvent medium, at temperatures between 35 and 65 centigrade and for periods of time ranging from 2 to 24 hours, a 3-ethylene ketal of the formula HaC 18 11. In a process for the manufacture of compounds of enolic formula wherein Z is a member of the group consisting of carbonyl, B-hydroxymethylene, and p-(lower alkanoyloxy)- methylene radicals and radicals of the formula R and R" being selected from the group consisting of hydrogen, and hydroxy and lower alkanoyloxy radicals, the step which comprises contacting in carbon tetrachloride medium at 50 to 55 centigrade during 15 to 20 hours, a S-ethylene ketal of the formula z Hi0 I CHI-O Hr-O with a mixture of tertiary butyl chromate, acetic acid,

and acetic anhydride, Z in the formula for the ketal being a member of the group consisting of carbonyl and fi-(lower alkanoyloxy)methylene radicals and radicals of the formula CHzRZ wherein R and R" are selected from the group consisting of hydrogen and lower alkanoyloxy radicals.

References Cited in the file of this patent UNITED STATES PATENTS 1 2,824,882 Marshall Feb. 25, 1958 2,836,608 Fried et a1. .4 May 27, 1958 2,862,935 Marshall Dec. 2, 1958 OTHER REFERENCES Lenhard: J.A.C.S., March 1956, pages 989-992.

Heulser et al.: Helv. Chim. Acta, 35, pages 284-289 (1953).

Oppenauer: Chem. Abst., vol. 44, page 3871 (1950).

UNITED STATES PATENT OFFICE CERTIFICATION CORRECTION Patent No. 2 934 545 April 26, 1960 Charles W. Marshall It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 29, for "hydrxyandrosta" read hydroxyandrosta column 8, line 5, for "thte" read the column 13, line 55, for "my," read u column 15, lines 62 to 74, the formula should appear as shown below instead of as in the patent? column l5 line 75, for "11" read R column 16 line 14, for "enalic read enolic Signed and sealed this 25th day of April 1961.

(SEAL) Attest:

ERNEST W. fill/ DER DAVID L, LADD Attesting Officer I a I Commissioner of Patents 

1. A COMPOUND OF ENOLIC FORMULA 